The present invention concerns a road marking strip capable of resisting to the passage of snow plowing implements and the like provided with snow blades sliding on the road surface. The present invention also concerns an improvement in methods of laying the road marking strip and improved apparatus for laying the road marking strip on road surfaces which are generally but not critically bituminous. More particularly, the present invention deals with laying of the road marking strip in situ in rows with progressive pressing of the tape on the road surface.
The art of road signalization has undergone in the last few decades a great development corresponding to the development of the motorization. This art, together with means, devices and apparatuses for laying down road marking elements is characterized by several improvements including the developments of the applicant who has tested and manufactured many road marking materials and apparatuses. These developments are reflected in technical and scientific publications as well as in numerous patents of the applicant. Among the problems which have been considered and partly solved by the applicant are the problems which are related to road markings to be used in winter time and/or in Northern zones, which must resist snow plowing and keep their visibility at night. It is known in the prior art that the problem of visibility of the road marking at night, in the rain and in general under unfavorable weather conditions cannot be considered as solved, especially on main road ways, not withstanding the amount of money which has been spent for the solution of this problem. Removal of snow is performed in general by snow plowing machines provided usually with blades made of metal or metallic carbures and the like capable of resisting to wearing out caused by sliding above the road pavement. It is well known that in especially severe weather conditions the combination of lower temperature and abundant snow leads to the formation on the road surface of ice which becomes particularly compact and slowly soluble, resisting even to salt solutions. Its high crystallization makes necessary the use of metal or metallic carbures blades. However, the blades remove and practically destroy the optical elements provided for imparting to the road surface of a good visibility in the rain at night.
The applicant has conducted studies and experiments for improving the existing systems and means designed to operate under the action of snow blowing means. In the applicant's U.S. Pat. No. 4,129,673 it has been proposed to provide a prefabricated road marking strip protected from the destructive action of snow blowing means by protruding components acting as rails which jointly define a plane for sliding of the blades above the protruding elements. This solution has been proved to be particularly efficient in protecting the optical elements against the action of rubber blades and at low speed in the town use, as well as against the action of metal blades. However, the most important problem connected to the high speed traffic roads where the blades of snow blowing means are caused to slide at high speed remains practically not solved.
Applicant has also proposed road marking means provided with retroflective elements which can be lowered "as a flag", as disclosed for example in the U.S. Pat. No. 3,879,148.